A hydraulic actuator which is mounted on an air craft, for example, requires a light weight cylinder barrel for housing a reciprocating piston.
In order to reduce the weight of the cylinder barrel, a known method is to construct the cylinder barrel using a thin sheet metal liner reinforced with a reinforcing structure made of glass fiber or carbon fiber.
The thin sheet metal liner is formed in a cylindrical shape and string made of glass fiber or carbon fiber is wound around the outer circumference of the sheet metal liner. The string wound around the sheet metal liner is then cemented by a resin. The reinforcing structure thus formed increases the rigidity of the cylinder barrel.
With respect to such a reinforcing structure, although not for a cylinder barrel, JP2004-324852A issued by Japan Patent Office in 2004, proposes that a valve body of a solenoid valve be reinforced with glass fiber or carbon fiber.